ABSTRACT
The idea that human reasoning depends on mental models has arisen from two main sources. The first is disillusionment with the idea that human reason ing can be described in terms of psycho-logic or mental logic. It now appears that those aspects of thought that Piaget once conceptualized in terms of psy chologic are probably better treated in terms of mental models and the oper ations on them (Halford, 1992). Piaget’s empirical work has held up better than is often supposed, as I have argued extensively elsewhere (Halford, 1989), and many of his theoretical conceptions, including structure, schema, and assimilation, have reappeared in contemporary cognitive psychology (Hal ford, 1992). However the concept of psycho-logic has encountered a number of difficulties. One problem has been that it has proved very difficult to de fine a psycho-logic that convincingly captures the nature of human reason ing in anything more than a very approximate or restricted sense. Such attempts were made not only by Piaget (e.g., Piaget, 1947-1950, 1957) but also by Osherson (1974a, 1974b, 1975, 1976) and Braine (1978) but, despite their sophistication, these formulations have not led to any consensus about the nature of human reasoning.
